A series of hybrid hydrogels of poly(2-hydroxyethyl acrylate), PHEA, and graphene oxide, GAO, with GAO content up to 2 wt % has been prepared by in situ polymerization. Because PHEA has been used as biomaterial in various applications, has a side chain with the hydroxyl functional group and its mechanical properties are poor, it is a good candidate for reinforcement with GAO. Fourier transform (infrared) spectroscopy, atomic force microscopy, differential scanning calorimetry, the thermal, mechanical, and water sorption properties of neat PHEA and PHEA/GAO composites have been studied in order to elucidate the dispersion and interaction between both components. An increase in the water diffusion coefficient and dramatic changes in its mechanical properties are the most remarkable results. Thus, at a nanofiller load of 2 wt %, the novel materials present an increased diffusion coefficient higher than 380% and the elastic modulus is enhanced by more than 650% in dry state and by more than 100% in swollen state, both compared to neat PHEA. These results have been attributed to the excellent interaction between the matrix, PHEA, and the reinforcement, GAO, and could open the door to new applications in the field of biomaterials with higher structural requisites. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46158.